Etching metal (steel) to see microstructure

Using Nital (2-3% nitric acid in ethanol) to reveal steel microstructure. Loosen cotton swab tip, etch for 30-45 seconds to yield a visibly cloudy surface, dunk in water to stop etch, place swab in baking soda dish and cap acid container. Etching is a controlled corrosion reaction used to attack the chemically active areas like grain boundaries where the misalignment of atoms gives them higher surface energy. There may also be composition differences at grain boundaries or within certain phases which also enables preferred/accelerated corrosion at these locations.
Etching recipes starting on pg 77: www.buehler.com/assets/3DISSU...
Reference: vector.cnam.umd.edu/images/li...

[@dyingofcringe8839]

nital is better in reviving stone corpses instead of etching metal

[@sayaakami8533]

;)

[@cytzsoraya4511]

ah yes.. dr. stone

[@Smb.kmm12]

A man of culture

[@Stoner_matics]

Oh yeah anime

[@mogaming163]

yup

[@Engineer_MayDay]

Today I learned something new

[@shibbleswentworth]

Go here for etching recipes, pg 22 start www.buehler.com/assets/3DISSUE/US/SumMetGuide/index.html

[@josephwise7269]

Very interesting. I am a teacher at a high school. I was thinking to show the kids just how different low carbon steel is to high carbon we'd look at an etched sample under a microscope then perform some destructive testing. It really doesn't look very difficult - can you pre-prepare samples though and they stay "etched"?

[@shibbleswentworth]

Cast iron has a cooler looking structure because of graphite flakes and you can literally break it with a hammer. Same etch less time.

[@Thanh3596]

Is there any way to do this with household items?

[@gabrielpagan5713]

would you recommend this same procedure for low carbon fasteners? Usually, after sectioning/polish I will need to etch before microhardness to make sure the lead threads of the fastener (thread-forming fasteners) were induction hardened (thumbnail pattern)

[@shibbleswentworth]

yeah it should work

[@bramkuijer]

Does using the Nital remove any scratches left behind from mechanically polishing and make the specimen good enough for EBSD?

[@joannecatherine3335]

No you should try to remove all scratches in the polishing process, may be an additional finer final stage would help.

[@shibbleswentworth]

vibratory polisher or automatic polishing equipment would be best

[@anasaltarifi466]

Is
Nitric acid
hydrochloric
Acetic acid
Glyserol
Can etch aluminum alloys?

[@shibbleswentworth]

aluminum can be etched by kellers reagent, and i think dilute aqua regia

[@eugenekrabs6729]

Soda is just crunchy water

[@venkataajaykumarmuvva4881]

hai Adam can you please send the etching solution list with chemical formulas Asap I am doing a project on NiTi material
if it possible can you suggest the solution for Niti Microstructural analysis using SEM, please.

[@shibbleswentworth]

I would try Keller's reagent, Google the recipe. if that doesn't work, dilute aqua regia. Different etches to examine different element and phase distribution.

[@jaijawaanjaikisan3658]

Can u please suggest etchant for magnesium alloy az61grade

[@myrmesuwu607]

Water... just kidding

[@shibbleswentworth]

Glycol etch 25ml water 75ml 3-5 ethylene glycol 1ml nitric acid, swab 1-2 minutes

[@rafaelmoral8053]

Hi. Is there a more common substitute than HNO3 for etching?

[@85tkern]

I don't know if this post is still active but it really depends on what you want to observe. If you plan to observe the microstructure of the material under a microscope, you really need to use nital or picral. Anyone with the capability to polish a sample down to 0.05 um can surely etch a sample with one of these two solutions.
If you want to etch it for macroscopic examination, you can try HCl. I use reagent grade and dilute it myself but I'm sure you could get away with purchasing some muriatic acid at a hardware store. For a macro etch, you can get away with about a 600 grit finish.
I hope this helps. If I get any more questions, I could make a video if needed.

[@rafaelmoral8053]

@@85tkern thanks buddy, really appreciate!

[@omegablaze8008]

Hey man, can we get the .pdf of the paper you are looking into for what chemicals to use for different metals please.

[@theara5181]

yeah.. can i have the list to in pdf... im studying on microstructure analysis.. and method for sample preparation..

[@anasaltarifi466]

Sir can you suggest to me an aluminum alloy etchant to see the grain boundaries?

[@anasaltarifi466]

Sir any etchant withou HF because i dont have this acid

[@TreyMeyer1]

Keller reagent

[@betr8]

Why did he do that again?

[@jenniferfifer2373]

to see grain boundaries in the microstructure

[@taufiqshihab1171]

Can i use methanol for etching??

[@shibbleswentworth]

with an acid, methanol is just an alcohol won't do anything by itself. The ethanol in nital is basically used to keep oxygen away and distribute evenly on the surface